The present application relates generally to integrated gasification combined-cycle (IGCC) power generation systems, and more specifically to a method of assembly and apparatus for cooling syngas.
At least some known gasifiers convert a mixture of fuel, air or oxygen, liquid water and/or steam, and/or slag into an output of partially oxidized gas, sometimes referred to as “syngas.” In an integrated gasification combined-cycle (IGCC) power generation system, syngas is supplied to the combustor of a gas turbine engine, which powers a generator that supplies electrical power to a power grid. Exhaust from the gas turbine engines may be supplied to a heat recovery steam generator that generates steam for driving a steam turbine. Power generated by the steam turbine also drives an electrical generator that provides electrical power to the power grid.
In some known IGCC plants, hydro-carbonaceous feeds that include coal, petroleum coke and high-ash residual oils, are reacted with high purity oxygen (typically 95% oxygen purity) to produce syngas in a temperature range of 2200° F. to 2700° F. Heat in this syngas is recovered as the syngas is channeled from a radiant syngas cooler (RSC) to a convective syngas cooler (CSC). Known radiant syngas coolers that use radiation as the primary heat transfer mechanism generally cool the syngas to a range of about 1100° F. to about 1200° F. and generate high pressure steam therefrom.
At least some known radiant syngas coolers are very large pressure vessels that may extend over 30 meters in height and weigh more than 300 metric tons. Because of the large size and weight of such radiant syngas coolers, the coolers cannot be delivered to a site in a fully assembled condition. Rather, such coolers must be shipped in parts and assembled at the site. Known radiant syngas coolers use multiple flanges to couple a head portion of the radiant syngas cooler to a shell portion. However, the size and other logistical considerations may make the process of coupling the head portion to the shell portion time-consuming and/or costly. Moreover, because multiple flanges are used to connect the head portion, over time, the shell portion may develop leakage through adjacent flanges or components. Moreover, the use of multiple flanges may increase the overall weight to be added to an already heavy radiant syngas cooler.